What does Verna warn Richard about as far as Du Chaillu is concerned and how does Du Chaillu repond?

Sister Verna warns Richard that Du Chaillu will try to kill him. Richard can't believe that Du Chaillu would kill him after he saved her. Du Chaillu tells Richard that she is grateful that he saved her and always will be, but that no matter what, Richard is still a magic man and the magic men stole her people's land and turned it into the Valley of the Lost during the wizarding wars.